We live in a world that needs more and more electric power. It also needs this increasing power to be produced by a source that does not give off carbon dioxide. Carbon dioxide is a greenhouse gas that is causes global warming. What is necessary is a new energy source that does not create carbon dioxide. This new energy must also be present in large quantities in the world and must be able to be extract cheaply.
Power from osmosis has been known for years. There is also plenty of fresh water from rivers flowing into the ocean with salt water. These areas at the mouths of rivers that flow into the ocean could be used as a source of power.
Concentration cells have been known for years. These cells comprise two tanks of liquid that are attached together usually by a membrane or a salt bridge. If the cells contain solutions in which one solution is of a higher concentration than the other, the lower concentration solution will flow into the higher concentration solution. If electrodes are placed in each and are attached together electric will flow through the wire attaching the electrodes. The tanks will produce electricity until the two solutions are of equal concentration.
In nature, salt water in the ocean has a higher concentration of salt then freshwater in rivers. At a mouth of the river, the freshwater flows faster into the ocean water due to osmotic pressure. This energy could also be tapped by electrodes or turbines. Electrodes could be placed in the freshwater and in the ocean water.
Fresh water begins as water vapor that is evaporated from the oceans by solar energy. This water vapor rises in the atmosphere forms clouds, ultimately resulting in precipitation. Some of this precipitation occurs over land forming fresh-water lakes and rivers. Eventually, all of this fresh water makes its way back to the oceans, thus completing the cycle. In fact, throughout the world enormous quantities of fresh water is freely washed into the ocean each year as part of the naturally occurring water cycle.
Energy called the “free energy of mixing” (or “heat of mixing”) occurs when fresh water flows into salt water. The free energy of mixing reflects an increase in entropy of water (or other solvent) when it is transformed from its pure (fresh-water) state to its diluted (salt-water) state. It is a physical property of solvents, such as water, that they have a natural tendency to migrate from an area of relatively low solute concentration (lower entropy) to an area of relatively high solute concentration (higher entropy). Thus, an entropy gradient is created whenever two bodies of water or other solvent having differing solute concentrations are brought into contact with one another and begin to mix. This entropy gradient can be physically observed and measured in the well-known phenomena known as osmosis. It can also be physically observed and measured by a concentration cell.
Thus, a substantial amount of electric power can be generated by placing electrodes within a river and placing electrodes in the ocean and attaching those electrodes through a load. This electric power will be produced with no generation of carbon dioxide. It will have a low environment impact.
The other natural source of electric power from a concentration or entropy gradient occurs in salt water lakes and the ocean. Salt water is denser than freshwater. Thus the water in a salt water lake or the ocean has different concentrations of salt at different depth. By placing electrodes at different depth and attaching them to a load electricity will flow.
A battery can also be formed by saltwater and freshwater. This battery can be formed by taking a container and placing heavily concentrated salt water in the bottom and placing freshwater on the top. By placing electrodes in the bottom in the heavily concentrated salt water and placing electrodes in the top in the fresh water and hooking these electrodes to a load electricity will flow. Over time the salt water will defuse into the freshwater and ultimately electric will cease to flow. It is not necessary to use saltwater and freshwater. Any solute and solvent can be used. The only necessity is the difference in the concentrations.
A solar pond could also be used for a type of battery. In a solar pond, the bottom layer of water has a high salt concentration. The top layer of water has a low salt concentration. Thus by placing an electrode in the lower layer of heavily concentrated salt in the solar pond and placing an electrode in the upper layer of the much lower concentration of salt, a battery can be formed. By attaching the two electrodes to a load electric will flow.
A concentration cell can easily be changed into a rechargeable battery.
There are many sources of thermal energy in which there is only a small temperature difference between the source of the thermal energy and the sink. These sources include geothermal energy, ocean thermal energy, many solar sources, waste heat from engines, and differential between atmospheric temperature and ground temperature. These sources have large amounts of thermal energy. However, since the efficiency of tuning thermal energy into mechanical energy is based on the temperature difference, these sources can only change a small percentage of the thermal energy to mechanical or electrical energy. Due to this fact, even though there are many small temperature different thermal energy sources very little of this energy is used to produce power. The big reason for this is that the cost of engines that turn thermal energy into mechanical energy. Both Rankin engines and Sterling engines can turn low temperature difference thermal energy into mechanical energy. However, both these types of engines are expensive. The object of this invention is to produce an engine that will change small temperature different thermal energy into mechanical energy efficiently that is very inexpensive to manufacture and run.